Method and apparatus for winding yarn



6 Sheets-Sheet 1 B. K. JOHNSON ETAL METHOD AND APPARATUS FOR WINDINGYARN Jan. 13, 1970 Filed April 5, 1965 Jan. 13, 1970 B. K. JOHNSON ETAL3,488,938

METHOD AND APPARATUS FOR WINDING YARN Filed April 5, 1965 s Sheets-Sheet2 11/1/11 I I II I! I II B. K. JOHNSON ETAL 3,488,938

METHOD AND APPARATUS FOR WINDING YARN 6 Sheets-Sheet 5 5 SID/N015 5/ 550(Relax/0 1 Jan. 13, 1970 Filed April 5, 1965 Jan. 13, 1970 B. K. JOHNSONETAL 3,488,938

METHOD AND APPARATUS FUR WINDING YARN Filed A r'ns, 1965 v eSheets-Sheet 5 Jan. 13, 1970 B.- K. JOHNSON HAL METHOD AND APPARATUS FORWINI DING YARN 6 Sheets-Sheet 6 Filed April 5, 1965 United StatesPatent.

3,488,938 METHOD AND APPARATUS FOR WINDING YAI N Bryan K. Johnson,Abergavenny, and Frederick A. Smith, Malpas, Newport, England, assignorsto British Nylon Spinners Limited, Pontypool, Monmonthshire, EnglandFiled Apr. 5, 1965, Ser. No. 442,858 Claims priority, application GreatBritain, Apr. 4, 1964, 13,986/ 64 Int. Cl. D01h 13/00; D02g 3/02 US. Cl.57-98 11 Claims ABSTRACT OF THE DISCLOSURE An apparatus and process forthe preparation of cylindrically-wound yarn packages characterized by arelatively high helix angle and reduced ridging, the process includingprogramming means arranged to control the winding conditions by varyingwinding speeds in a manner such as to reduce ridging.

This invention relates to a method and apparatus for winding yarn in theform of cylindrically-wound packages, in which the yarn is laid with arelatively high helix angle, and associated therewith is drive meansincluding means by which the speed of the spindles on which the packagesare being formed is variable during the winding of the packages.

The term cylindrically-Wound package used above refers to packages inwhich at least a part of each layer of yarn is wound so as to form partof a cylindrical portion of the package (although not necessarily aright cylinder). Thus, the packages may be wholly of cylindrical formi.e. cheeses, or be of other forms of build, such as conicalendedpackages of, for example, pirn or long-to-short build.

Further, for convenience, in this specification, the chuck o-r spindleupon which the package container is clamped during the winding operationwill be referred to as a spindle, irrespective of whether a whollycylindrical package or a conically-ended package is formed thereon.

The term helix angle is used in this specification to refer to themaximum angle of inclination of the curve representing the developedview of the lay of the yarn on the package, to the mean axis of thiscurve, and a relatively high value for this angle is an angle in excessof 1, although it may vary throughout the winding of a package.

The kinds of winding apparatus to which the present invention appliesare as follows:

(a) Apparatus for the formation of wholly cylindrical packages,hereinafter for convenience referred to as cheeses, having a rotatingspindle and reciprocating traverse yarn guide means, the spindle speedbeing proportional to the ratio of the yarn delivery speed to thepackage diameter while the traverse guide speed is variable,independently of the spindle speed, at will (as compared to windingarrangements in which the spindle and yarn traverse guide means aredriven by common driven means, and at speeds which are not independentlyvariable, except by an interruption of the driving of one or bothparts).

There are predictable points during the winding operation of either formof such winding apparatus, when the number of spindle revolutions pertraverse cycle of the yarn guide is either a small integer or a ratio ofsmall integers at these points, hereinafter referred to as wind ratios,these wind ratios corresponding to periods during the winding opeationwhen the yarn in one layer of the package is laid directly on the yarnof layers laid immediately previously, at these wind ratios thissynchronisation of the winding causing ridges of yarn to be producedwithin the package structure.

It will be understood that, in such a winding arrangement, the windingconditions at any particular package diameter, comprise the spindlespeed, traverse yarn guide speed and the yarn delivery speed.

(b) Apparatus for winding, say, a conica1ly-ended package, having adriven spindle and over-end yarn guide means, for example, a ring andtraveller guide device, the yarn being laid on the package in the formof closely wound helical turns with a sinusoidal wave-form superimposedthereon, due to, say, the axis of the ring of a ring and traveller yarnguide device being inclined to the spindle axis.

For convenience hereinafter such packages produced by over-end windingapparatus will be referred to as conically-ended package.

The winding apparatus will be assumed to include a ring and travelleryarn guide device, although other forms of over-end winding such ascap-spinning would also be applicable as they usually have tapered endportions.

In such a case, on either side of certain predictable points in thewinding operation, parts of the sinusoidal curves of yarn merge togetherto produce a fine patterned effect in the surface relief of the package.

The winding conditions associated with such a winding arrangement, andat any particular package diameter, comprise the spindle speed, thewinding-on speed of the yarn, the traveller speed, the type of build ofthe package and the angle of inclination of the axis of the ring to thespindle axis.

For any over-end winding arrangement for producing comically-endedpackages it is possible to derive the following equation:

in which S is the spindle rotational speed, T is the ro tational speedof the traveller (in the requisite units), and W is the fraction of thespindle rotational speed corresponding to the winding-on of the yarn.

The winding speed W of the yarn is equivalent to the package rotationalspeed in the case of the cheese winding operation referred to above, andwould be equal in magnitude to the spindle rotational speed if thetraveller was stationary (i.e. T :D).

The points associated with the patterning, on the package in the windingof comically-ended packages correspond to the wind ratios of the cheesewinding arrangement, and are when the ratio of T:W is either a smallinteger or a ratio of small integers.

These ratios also may be called wind ratios, and are equivalent to thewind ratios referred to above with respect to the formation of cheeses,although the manner of formation of ridges on cheeses dilfers from thatof the patterning on the comically-ended packages, and both the problemof the reduction of ridging and the reduction of patterning may besolved in equivalent ways.

The present invention is especially concerned with overend windingapparatus in which it is possible to control the value of S at will, andeither consequently, or otherwise, to control some such aspect of thewinding operation throughout the production of a comically-endedpackage.

The value of the term T may be varied at will, or be maintained at aconstant value, by appropriate changes in the value of S (the value of WVarying so that the relation S=T+W is obeyed). Thus, the windingconditions may be chosen so that certain desired objects are achievedwith respect to the production of the yarn packages, for example, sothat the balloon tension of the yarn is maintained at a substantiallyconstant value throughout the winding operation to produce a yarnpackage.

In this case, the winding apparatus includes programming means so that,the spindle speed S is varied through out the winding operation, in amanner ensuring that T is proportional to the package diameter, and thusthe Jalloon tension of the yarn is maintained at a substantiallyconstant value, barre being reduced in fabrics produced :rom syntheticpolymer yarns so wound. In this respect, he traveller of a ring andtraveller device can be assumed to be a wind-on guide whose speed isproportional to :he yarn tension, and not solely as a means of inserting:wist into the yarn, the function of a ring and traveller yarn guide,including the insertion of twist into the yarn and ensuring that astable balloon is maintained by ten- ;ioning the running yarn to therequisite amount.

The tension in the running yarn is usually adjusted so to approximate toits minimum acceptable value for 1 stable balloon, so that a containerconstruction which is is flimsy as possible may be used.

The uniform tensioning of the yarn throughout the fornation of thepackage, implies that defects in fabrics nade of synthetic polymer yarnsso wound, such as barre )1 warp-stripes are reduced. Yarns taken fromsuch packlges will also have a better warping performance.

Alternatively, the winding programme, for an over-end voundcomically-ended package, may be arranged to en- ;ure that the yarn guidemoves at a constant speed, so as o minimise strain within the yarn guidedevice, but with l gradually reducing yarn tension throughout thewinding )peration.

There is also the effect, associated with synthetic linear olymer yarns,which causes the retraction in length of .he yarn over a prolongedperiod after it has been renoved from a package and is not maintained intension. For convenience hereinafter, this effect will be referred :o asair retraction, and is measured normally by noting, )ver an extensiveperiod of time, the change in length of 1 yarn, which yarn when freshlyremoved from a package s subjected to only sufiicient load to keep theyarn straight n air and free to retract. It is found that the greatestnagnitude of this effect is associated with yarn taken from near to thecore of the package, is less with yarn .aken from the middle of thepackages (after approxinately a quarter of the package has been wound),and hen rises again with yarn from the outer layers of the package.

This effect can be reduced by decreasing the spindle xpeed at theperiods in the winding programme corresponding to high air retraction,and vice versa. The action of :he winding apparatus in this case, isclosely associated to :he manner of operation for maintaining at aconstant value the balloon tension of the yarn, referred to above (inthis case, of course, the balloon tension being deliberitely varied in apredetermined manner during the windlng operation to achieve the desiredobject).

Similarly, the spindle speed may be programed during :he windingoperation, causing the yarn balloon tension to vary, but controlling thevalue of the yarn denier, or its initial modulus, or the twist insertionrate.

It will be appreciated, that in any event, the maximum productivity ofany given winding apparatus will only 3e realised if the maximum yarndelivery speed is em- Jloyed, and this factor may have to be taken intoaccount when programming the winding apparatus.

In this connection, a further reason for reducing the ipindle speedduring the winding operation, is to ensure .hat, as the inertia of thecontainer and package increase, :he torque on the spindle does notexceed the maximum lesign specification for this part of the windingmachine, if the torque on the spindle is kept as close to the designlPCCifiCHIlOI'l value as possible, the maximum attainable :fficiency ofthe winding apparatus may be obtained.

In addition to programming the winding apparatus in )rder to obtain anyone (or combination), of the above lesired objects, it is also possibleto ensure that the packige has an adequate stability, by providing thatthe turns )f the yarn, particularly if it is a synthetic polymeric mmwith a relatively smooth surface, cross over each other at a relativelyhigh helix angle, so as to interlock one with another.

This desired object may be obtained by, say, tilting the axis of thering of a ring and traveller device, in the case of the over-end windingof a conically-ended package, (or by having a high traverse frequencyassociated with the winding of cheeses).

Further, it is desired that the axis of the ring of a ring and travellerdevice inclined to the spindle axis, so that, in addition to the packageso produced having increased stability, the take-off tension associatedwith the final layers of yarn, to be unwound from such a package, isless than that associated with a package wound without ring tilt.

In practice, all rings will tilt, perhaps unintentionally due to themounting of the ring, but the extent of the patterning within thepackage usually, will be greater when the ring tilt angle isintentionally arranged to be finite, this value normally being greaterthan 1, and possibly greater than 3. Unfortunately, it is just theabove-mentioned conditions, for package stability which cause patterningto be formed on comically-ended packages (and ridges to be formed oncheeses).

In a cheese winding arrangement, in which the reciprocating motion ofthe traverse guide has a relatively high frequency associated therewith,then ridging will occur, as the criterion for enhanced ridging ispresent, i.e. that there should be a relatively high helix angleassociated with the manner in which the yarn is laid, When a hightraverse frequency is employed, e.g. when approximately 20 wraps of yarnare placed on the container in a traverse stroke the helix angle will bein excess of, say, 1.

However, with a relatively low traverse frequency, the helix angle mayhe, say, V and ridging in this case is not pronounced. Similarly, withthe international tilting of the axis of the ring of a ring andtraveller yarn guide, with respect to the spindle axis, the helix angleusually will be of the order of 3 or above.

The ridging on the cheese packages counteracts any increase in packagestability, due to the employment of a relatively high traverse speed,and increases the tendency of the yarn to slough, when it occurs. Thisis because the layers of yarn are not securely laid, at those points,and further, in this case and in the case of patterning onconically-ended packages, it may be the source of uncontrollablevariations in the take-off tension of the yarn, and is, in any event,unsightly.

Further, with packages having ridging or patterning, the yarn thereon,if subject to retraction on the package, will be unevenly stressed whilein the form of the package, and hence streaks may occur in the fabricinto which such yarn is made up, as these stress differences are thecause of barre and are a cause of warp stripes in woven fabrics.

It has been known, with respect to cheese winding machines of the typein which the package is caused to be rotated by frictional contact witha grooved cylindrical driven traverse drum, or by a drive roll whichalso drives the traverse drum, the ridging of the yarn on the package insuch a case being particularly obvious when it occurs during the windingof the package as compared to the type of cheese winding apparatushaving a spindle and yarn traverse guide means which may be driven sothat the speed of one is variable independently to the other at will andto which the present invention applies, to associate the most enhancedperiods of such ridging with predetermined ratios of the reciprocatingtraverse yarn guide speed and the winding-on speed.

In these prior arrangements, the normal winding operation has beeninterrupted in a cyclic manner, by imposing a periodic variation on thewinding-on speed continuously throughout the winding of a package,perhaps by applying a brake, or by causing the package to sliprelatively to the traverse drum or drive roll.

It is an object of the present invention to provide winding apparatusincluding means to enable the winding operation to be programmed, and soto cause the patterning or ridging within a package to be reduced tonegligible proportions, by eliminating, or at least reducing the extentof the occurrence of those wind ratios corresponding to the mostenhanced patterning or ridging in the winding operation. I

As stated above, the periods of most enhanced patterning oncomically-ended packages, and of ridging on cheeses, occur atpredictable points'in the winding operation, these points being when thewind ratio is either a small integer or a ratio of small integers. Inboth cases, these points are associated with certain package diameters,the values of these diameters being calculable from a knowledge of thewinding conditions pertaining to the formation of the package.

The wind ratios which correspond to the most enhanced patterning onconically-ended packages are as follows, given in an approximately orderof decreasing magnitude of the effects:

1:1; 2:1; 3:1; 1:2, 3:2 and 5:2; 1:3, 2:3, 4:3, 5:3, 7:3 and 8:3; etc.

It will be appreciated that the numerical value of the wind ratioincreases progressively as the package is being formed.

The above list is composed as a result of making the assumption, whichwill generally be true for conicallyended packages, that of the possibleratios, the integers 4:1 and above; and the simple fractions 7:2 andother multiples of 1:2; 10:3 and other multiples of 1:3 etc. will notoccur in the winding of the package.

In order to reduce patterning to negligible proportions, the patterningassociated with any of the wind ratios listed above should beeliminated, or substantially reduced in the winding of a package, andpossibly also the wind ratios which are multiples of 1:4 up to 11:4.

With respect to cheeses, the wind ratios which correspond to the mostenhanced ridging and which will generally occur in the winding of thepackage are: the inte gers 2:1; 3:1; up to 8:1; and the ratios of smallintegers in between these values.

According to the present invention, winding apparatus for producingcylindrically-wound packages, in which the yarn is laid with arelatively high helix angle, there being a predetermined point or pointsduring the formation of such a package associated with a period orperiods during which the package is patterned or ridged, each suchperiod corresponding to winding conditions having associated therewith aWind ratio (as defined above) the numerical value of which is either asmall integer or a ratio of small integers, includes programming meansarranged to control the winding conditions and to cause an increase inthe numerical value of the wind ratio at the predetermined point orpoints in the winding operation, so as to reduce the extent of theperiod or periods of enhanced patterning or ridging in the formation ofthe package.

It will be appreciated that if a period of patterning or ridging is tobe traversed effectively this could be in a manner which either causedthe numerical value of the wind ratio to be either increased ordecreased. However, if the value of the wind ratio is decreased, perhapsby a form of scrambling device, then the period of patterning or ridgingassociated therewith will have to be traversed again as the formation ofthe package continues, by causing the value of the wind ratio toincrease. Hence if the value of the wind ratio is increased as eachpredetermined period of enhanced patterning or ridging is approached,then the periods will only have to be traversed once in each windingcycle.

Hence, over-end winding apparatus for producing conically-ended packageson a spindle in which package the yarn is laid with a relatively highhelix angle, has programming means arranged to increase the speed of thespindle at the predetermined point or points in the winding operation,so as to reduce the extent of the period or periods of enhancedpatterning in the formation of the package.

In one construction, the programming means for the spindle drive meansincludes a profiled cam arranged to make one revolution between thewinding of successive packages, and embodying the desired spindle speedprogramme, the cam controlling the spindle speed in such a manner thatat the selected points during the Winding of each package this speed isincreased.

Conveniently, the programming means comprises an electrical device andincludes a potentiometer, position of the slides of this potentiometerbeing controlled by the cam, and the output signal from the programmingmeans controlling the output of a synchronous electric motor driving thespindle on which the package is formed, this motor only driving thespindle.

In addition, winding apparatus for producing cheeses having a rotatingspindle, the rotational speed of the spindle being arranged to beproportional to the ratio of the yarn delivery speed to the packagediameter, and reciprocating traverse yarn guide means the speed of whichis variable independently of the spindle speed at will, and in whichpackage the yarn is caused to be laid with a relatively high helixangle, has programming means arranged to decrease the speed of thetraverse yarn guide at the predetermined point or points in the windingoperation, so as to reduce the extent of the period and periods ofenhanced ridging in the formation of the package.

According to another aspect, the present invention resides in a methodof producing cylindrically wound packages, in which the yarn is laidwith a relatively high helix angle, there being a predetermined point orpoints during the formation of each such package associated with aperiod or periods during which the package is patterned or ridged, eachsuch period corresponding to winding conditions having associatedtherewith a wind ratio (as defined above) the numerical value of whichis either a small integer or a ratio of small integers, comprisescontrolling the winding conditions to cause an increase in the numericalvalue of the wind ratio at the predetermined point or points in thewinding operation, so as to reduce the extent of the period or periodsof enhanced patterning or ridging in the formation of the package.

In one form, in a method for producing a conicallyended package on aspindle by over-end winding, and in which package the yarn is laid witha relatively high helix angle, the speed of the spindle is increased atthe predetermined point or points in the winding operation so as toreduce the extent of the period or periods of enhanced patterning in theformation of the package.

In one method of winding comically-ended packages (particularly of theso-called long-to-short build), the spindle speed is arranged to bereduced throughout the winding of each package, except at thepredetermined point or points, when the spindle speed is increased.

The program of the spindle speed may be such that optimum windingconditions are adopted where two features included in the programme aremutually inconsistent, the first feature being related to controllingthe spindle speed so that this speed is increased at the predeterminedpoint or points, and the second feature being related, say, tocontrolling the spindle speed so that this speed is reduced in a mannertending to maintain a constant value for the balloon tension of the yarnthroughout the winding operation.

The allowable increase in spindle speed at any point in the windingoperation will be limited, so that the winding-on tension in the yarn isnot increased beyond an unacceptable level, or the change in winding-ontension is not so great as to render the properties of the yarn 'woundunder this higher tension markedly different from the properties ofadjacent layers of yarn, i.e. such that 7 it will be recognisable asstreaks in the fabric into which the yarn is made-up.

However, a change in spindle speed from a value 10% aelow thenormally-desired value at each predetermined point in the windingoperation, to a value 10% above :his normally-desired value at eachpredetermined point, will generally have no recognisable adverse effectson the yarn or the fabric into which the yarn is made.

The increase in spindle speed at each predetermined point, and embodiedin the spindle speed programme, may be arranged to be the minimumrequisite value in Jrder to reduce substantially the patterning at thatpoint in the winding operation, the value of the increase varyingbetween different predetermined points.

In one arrangement the requisite increase in spindle speed at eachpredetermined point in the winding op- :ration is arranged to beeffected during a period less :han 0.5% of the package winding period.

Alternatively, in a method of winding cheeses on a spindle in which therotational speed of the spindle is arranged to be proportional to theratio of the yarn deivery speed to the package diameter, and the speedof 1 reciprocating traverse yarn guide is arranged to be independentlyvariable of the spindle speed at will, and n which cheese the yarn islaid with a relatively high 1elix angle the speed of the traverse yarnguide is de- :reased at the predetermined point or points in the windngoperation, so as to reduce the extent of the period )r periods ofenhanced ridging in the formation of the package.

Two embodiments according to the present invention and a modificationthereof, will now be described by avay of example, but not limitation,thereof, and with reference to the accompanying drawings, in which-FIGURE 1 is a diagrammatic representation of a draw :wist machine forproducing comically-ended packages 3y over-end winding,

FIGURE 2 shows one form of drive means for the nachine of FIGURE 1,

FIGURE 3 illustrates the cam used to control the spindle speed of thismachine,

FIGURE 4 is a graph of the spindle speed programme :hroughout thewinding of a package, when the winding apparatus is controlled by thecam of FIGURE 3.

FIGURE 5a shows the lay of the yarn on a conically- :nded packageproduced by the apparatus of FIGURE 1, when in a pattern-free condition.

FIGURE 5b shows the lay of the yarn on the package In a pattern-formingcondition,

FIGURE 50 is a developed view of the lay of the package and indicatesthe helix angle associated with such a yarn package,

FIGURE 6 is a cross-sectional view of a modifiec Form of control devicefor the spindle drive means of the nachine shown in FIGURE 1,

FIGURE 7 shows diagrammatically a cheese winding irrangement accordingto the present invention in which :he traverse yarn guide is oscillatedat a speed varying according to a predetermined programme,

FIGURE 8a shows, in an exaggerated manner, the ay of yarn on a cheeseduring a ridge-forming condition )f the winding apparatus of FIGURE 7,and

FIGURE 8b is a developed view of the lay of the yarn )f the cheese, andindicating the helix angle, 0 associrted therewith, this angle inpractice being of the order f 1.

The apparatus shown in FIGURE 1 comprises a drawvwist machine fordrawing a yarn made of a synthetic iolymer, for example, a polyamide,and for collecting he drawn yarn in the form of a comically-endedpacktge by means of over-end winding.

The yarn 1 is withdrawn from a cheese 2 mounted on 1 container 3, andpasses through yarn guide means, inlicated at 4, to a pair ofco-operating feed rolls and 6. From these feed rolls the yarn is wrappedaround an Cir inclined snubbing pin 7, which causes a considerablephysical restraint to be imposed on the yarn, resulting in the yarnnecking and being stretched to, say, five times its original length. Theyarn then passes around draw rolls 8 and 9, which forward the yarn at aspeed five times greater than it is forwarded by the feed rolls 5 and 6.

After the draw rolls 8 and 9, the yarn passes through a balloon guide 10to the winding apparatus, where it is wound onto a package 11 rotatablymounted on a vertically extending spindle 12. The yarn guide means,casing the yarn to be laid on the package, comprises a conventional ringand traveller device 13 mounted on a ring rail 14, this ring rail 14being reciprocated along the spindle axis by a known form of buildermechanism, including a striker plate 15 secured to the ring rail 14 forreciprocation therewith. At each end of each reciprocation stroke theplate 15 is arranged to operate a microswitch 16 or 17, and so causingthe reversal of the direction of movement of the ring rail. Thepositions of the microswitches 16 and 17 are controlled respectively bytwo cams 18 and 19, rotatably mounted on a shaft 20 driven at a constantspeed.

In the embodiment illustrated in FIGURE 1, the builder mechanism isadjusted so that a long-to-short package is produced, the distancebetween the microswitches, and consequently the stroke length of thereciprocation of the ring rail 14 along the package axis, continuouslydecreasing throughout the winding operation, the cams 18 and .19rotating through 330 during the winding of each package.

In order to improve the stability of the package, the axis of the ringof the ring and traveller yarn guide device 13 is inclined at an angleof 3 to the axis of the spindle 12. Thus, the yarn is laid on thepackage in the form of closely-wound helical turns on which issuperimposed a sinusoidal wave-form due to the inclination of the ringcausing the traveller to have a small amplitude oscillating movementalong the spindle axis. This sinusoidal component of the lay of the yarnon the package, causes the yarn to interlock, and so is less liable tosloughing, but does cause the yarn to form a surface relief pattern onthe package at certain diameters as the package is being formed.

FIGURE 2 shows a convenient form of drive means for the draw-twistmachine illustrated in FIGURE 1. This drive means comprises asynchronous electric motor driving a shaft 26 at a constant speed, thisshaft being coupled to the feed rolls 6 and 7, and the draw rolls 8 and9 of the machine. A second constant speed shaft 27 also is driven by themotor 25, and in turn drives a third constant speed shaft 28, throughco-operating pinions 29 and 30.

The shaft 27 is coupled to a variable pitch pulley 32, and the spindle12 is driven by the motor 25, through this variable speed device 32,shaft 33, and the shaft 27. The pitch of the pulley 32, and consequentlythe spindle speed, is controlled by the position of a lever 34 coupledto the variable pitch pulley 32. This lever 34 carries a cam follower 35arranged to engage a cam 36 (shown in FIG- URE 3, but not shown inFIGURE 2), this cam 36 being rotatably mounted on the arm shaft 20,which is driven at a constant speed from the shaft 28.

Thus, the spindle speed is varied throughout the winding of a package inaccordance to the profile of the cam 36, the spindle 12 being driven bythe motor 25 via the variable speed device 32, which is controlled bythe cam 36 through the cam follower 35 and lever 34.

The cam profile, which embodies the spindle speed programme throughoutthe winding of each package incorporates the features that the spindlespeed reduces throughout the winding of each package, except at thosepoints in the winding operation at which enhanced patterning of thepackage surface occurs these points corresponding to certain predictablepackage diameters. This feature of the spindle speed programme, beingillustrative of the present invention, will be referred to in detailbelow, with reference to the data presented in the form of the graphcomprising FIGURE 4.

The cam 36, illustrated in FIGURE 3, causes the spindle speed to bereduced from its initial high value, at40 on the cam profile, to itsfinal, relatively low value at 41. There are three intermediate points42, 43, and 44, which comprise protrusions on the generally-reducingradii of the cam, these points corresponding to points in the spindlespeed programme at which the spindle speed is relatively sharplyincreased (but not instantaneously increased).

With respect to the feature of the Winding programme, that the spindlespeed should be reduced during the winding of each package, of thepossible types of build for comically-ended packages, with which thepresent invention is concerned, the long-to-short build, in which thering rail has a continuously reducing reciprocating stroke lengththroughout the winding operation, is particularly advantageous when areducing-spindle-speed programme is desired, as in this case the maximumproductivity is possible from the winding apparatus.

With respect to the other comically-ended package builds limitations inspeed are necessary as the package grows, due to the possibility ofexcessive torque being applied to the spindle, or the traveller of aring and traveller yarn guide device exceeds its maximum desirable speedand is subjected to excessive wear.

The advantages are to be obtained if the spindle speed is reduced duringthe winding of a package are illustrated in the following example.

EXAMPLE A constant-spindle-speed device has a maximum acceptablerotational speed for a full package of 4.5 inches diameter on a 2 inchesdiameter container of 5000 r.p.m. If the device has a constant yarndelivery speed of 1,330 feet per minute, the traveller speed increasesfrom 3,000 r.p.m. to 5,080 r.p.m. during the winding of the package.

The spindle-speed of the reducing spindle-speed apparatus, winding anequivalent package may start at 8,630 r.p.m. the yarn delivery speedbeing constant throughout the winding operation at 3,200 feet perminute, and the traveller speed being constant at 3,000 r.p.m.

Thus, winding apparatus with a reducing-spindle-speed device hasincreased productivity by over winding apparatus employing a constantspindle-speed throughout. Further, the traveller speed has been reducedby a maximum value of 41% and so reduced the possible stress within thispart of the apparatus.

Further, the long-to-short package build, referred to above, alsoenables the balloon tension yarn and hence the yarn take-off tension tobe controlled, is controlled, the balloon tension of the yarn beingmaintained substantially at a constant value throughout the windingoperation if the spindle speed is arranged so that the square of thetraveller speed is proportional to the package diameter as the packageis being formed. Thus, the winding apparatus having areducing-spindle-speed device may be programmed to achieve this desiredobject.

The graph shown in FIGURE 4 indicates a suitable spindle-speed programmefor the production of a longto-short comically-ended packages of 70denier multifilament yarn having 34 constituent filaments, the yarnbeing delivered at 1740 feet per minute. The graph is of spindle speedagainst package weight (this latter co-ordinate being converted topackage diameter, as indicated by the axis 50), for a package of aparticular overall length.

On this graph, the chain line 51 indicates how the spindle speed shouldbe reduced in order to obtain a constant value of the balloon-tension ofthe yarn on the package throughout the winding operation, this valuebeing 8 grams, or approximately the desired minimum value formaintaining a stable balloon, namely 0.1 gram per denier. As can be seenfrom FIGURE 4, in such a case the spindle speed decreases graduallythroughout the formation of the package from an initial value of 9,200r.p.m. to 7,200 r.p.m.

Superimposed on this curve 51 are three curves 52, 53 and 54,respectively, representing the three periods at which the most enhancedpatterning occurs during the formation of the package, i.e.corresponding to a wind ratio of 1:2, curve 52 to a wind ratio 1:1,curve 53; and to wind ratio of 3:2, being indicated by curve 54.

Each curve is given by the general formula:

where S is the spindle speed (r.p.m.)

Del is the yarn delivery speed (inch/minute),

D is the package diameter (inch), and

P is the numerical value of the wind ratio. S=T+W, Where T is thetraveller speed (r.p.m.)

It will be appreciated that, although the curve corresponding to eachwind ratio is represented by a line, in fact patterning will occur oneither side of this line, and each line represents the mean of apatterning zone on the graph.

At the points of intersection between the curve 51 and the curves 52,53, 54, then the package wound according to the spindle speed programmeembodied in the curve 51 will have enhanced surface patterning.

Consequently, in order to eliminate this patterning, or at least toreduce the extent to which it occurs, a revised winding programme ischosen, this programme being represented by the line 55 on the graph andembodied in the cam 36.

As can be seen from FIGURE 4, this Winding programme, and imposed by thecam 36 of FIGURE 3, initially, causes the yarn to be wound under thedesired balloon tension of '8 grams, but gradually falls below thisvalue, to a value of approximately 7 grams, when the first patterningzone is approached (corresponding to the wind ratio 1:2). The spindlespeed is then relatively sharply increased by approximately 10%,indicated by the portion 56 of the line 55, causing the balloon tensionto rise to 9 grams.

Thus, the patterning zone, is traversed quickly, compared to the windingprogramme embodied in the line 51 and say, during the laying of twolayers of yarn on the package, for the surface relief pattern effect tobe observed.

The spindle speed is then caused to be gradually reduced until the nextpatterning zone is encountered at 57 (corresponding to wind ratio 1:1).Intermediate between these two zones 56 and 57, the line 55 on the graphcrosses the line 51 corresponding to the constant balloon-tensionWinding programme, the spindle speed being caused to 'be reduced at agreater rate than that required for this latter programme. Thus thevalue of the balloon tension will have dropped from 9 grams to 7 gramsduring this period.

The patterning zone corresponding to the wind ratio 1:1 is traversed inlike manner to that described above with reference to the wind ratio1:2. Again, the spindle speed is relatively sharply increased, byapproximately 10% (although it may be necessary to have a greaterincrease in the spindle speed in order to eliminate patterning at thispoint 51 in the spindle speed programme 55). The balloon tension againrises to about 9 grams in value.

This procedure is repeated with respect to the patterning zonecorresponding to the wind ratio 3:2, the spindle speed being graduallyreduced from the point 57, until it is at a value approximately 5% belowthe corresponding value on the constant balloon tension curve 51, at thepoint 58, it then being sharply increased to 5% above this value, and sothe patterning zone is traversed, and

patterning is not formed on the package surface at this point 58 in thespindle speed programme 55.

It will be appreciated that with the Spindle speed programme 55described above reducing the spindle speed throughout the windingoperation, the intersection points 56, 57 and 58 between wind ratiocurves 52, 53, 54 and the programme line 55 will occur at pointscorresponding to larger package diameters, compared to a programmerequiring a substantially constant value for the spindle speedthroughout the winding operation. Hence, it is relatively easier for thewinding apparatus to be programmed so as to avoid the regions ofenhanced patterning during the formation of packages.

During the winding of packages according to such a spindle speedprogramme 55, the rate of twist insertion in the yarn will fluctuate,but the overall value for this rate will vary only from approximately0.25 t.p.i. at the initiation of the winding operation, to 0.17 t.p.i.at the outer layers of the package. Such a variation in the twistinsertion rate will not be noticeable in the appearance of fabrics intowhich the yarn is made, particularly as the mean insertion rate is a lowvalue, and hence the variations in the winding conditions embodied inthis programme are normally acceptable.

To summarise, the steps taken in the preparation of a suitable spindlespeed programme are as follows:

(1) Calculate the volume of the conically-ended package at variousdiameters, and plot a graph 50 of the diameter of the package againstits weight,

(2) Calculate the spindle speeds required, for any given yarn deliveryspeed; in order to give a constant balloon tension throughout thepackage at the various diameters, and a graph 51 of spindle speedagainst package diameter plotted for constant balloon tension isobtained.

(3) The curves 52, 53, 54 associated with the wind ratios, correspondingto the periods of most enhanced patterning throughout the windingoperation, are plotted at various spindle speeds and diameters, and aresuperimposed on the graph 51 prepared under paragraph 2, and theintersection points 56, 57, 58, respectively, are noted,

(4) Select a cam control device, and calculate the increase in packagediameter per degree of angle of rotation of the cam, and

(5) Design a cam to suit the planned programme, which conforms to a line55, and which causes the spindle speed to be increased comparativelysharply at the points, 56, 57, 58, but consistent with the attainment ofthe second feature of the spindle speed programme, the line 55 conformsto the graph 51 as closely as possible, optimum values, for the spindlespeed being embodied in the spindle speed programme 55 at the points 56,57, 58.

The cam 36, shown in FIGURE 3 has protrusions 42, 43, 44 respectivelycorresponding to the points 56, 57 and 58 in the spindle speed programme55, the profile of the cam embodying the programme 55.

The appearance of the patterning on the surface of a conically-endedpackage, and the manner of its forma tion is indicated in FIGURE 5. Asstated above, the yarn is laid on the package in the form of closelywound helical :urns on which is superimposed a sinusoidal wave form,when the axis of the ring of the ring and traveller yarn guide device isinclined to the spindle axis. The maximum angle of the inclination ofthe curve representing the developed view of the lay of the yarn on thepackage, to the mean axis of this curve, is herein defined as the helixangle, and is the angle (0) indicated in FIGURE 50. When the value ofthis angle is relatively high, say, in excess of 1, which it usuallywill be if the axis of the ring is intentionally tilted with respect tothe spindle axis, then patterning of the package surface at certainpackage diameters occurs.

When each turn of yarn includes a small integral number of sinusoidalwaves, i.e. the value for the wind ratio.

T :W being a small integer, or each turn of yarn has a number ofsinusoidal waves which is a ratio of small integers, then the lay ofadjacent turns of yarn is represented by FIGURE 5a. However, immediatelyon either side of this point in the winding operation, the parts of thewaves having the maximum angle of inclination to the mean axis of thelay of the yarn on the package, i.e. the parts of the waves defining thehelix angle (0) shown in FIGURE 5c merge together in the manner shown inFIGURE 512.

It will be appreciated that this merging of the turns of yarn causesridges to be formed on the package surface, each ridge comprising only asmall part of the length of each turn, and being inclined at an angleapproximating to the helix angle (0) thereto. There may be more than oneridge associated with each turn of yarn, and in any event these ridgeswill be distributed over the package surface at this point in thewinding operation, so that a fine surface relief pattern effect isobtained.

The yarn lay shown in FIGURE 5a corresponds to, say, a wind ratio of1:1, while the yarn lay shown in FIG- URE 5b corresponds to a wind ratioof, say, 1.001: 1.

The numerical value of the wind ratio progressively increases throughoutthe winding operation; and in increasing the spindle speed at the points56, 57, 58, referred to above, the numerical value of the wind ratiowill be sharply increased at these points.

Care must be taken that in avoiding one region of patterning, thespindle speed programme is not such that the spindle speed increase endsin another zone of enhanced patterning, associated with a wind ratiowhich is either a small integer or a ratio of small integers.

The period taken to traverse any zone of enhanced patterning should beas short as possible. Thus at the predetermined points, for example,indicated at 56, 57, 58, the spindle speed programme should intersectthe wind ratio curves 52, 53, 54, at an angle approaching a right angle.

The magnitude of the requisite spindle speed increase in order totraverse one of these patterning zones will vary with difierent windratios, but generally will be less than 20% of the mean value of thespindle speed at this point, although such an increase may cause anexcessive increase in the balloon tension of the yarn. Hence, it may bedesirable to accommodate a certain amount of patterning at certainpoints in the winding operation, so as to avoid unacceptable adverseeffects due to other causes resulting from a large, relatively suddenincrease in spindle speed.

The most enhanced patterning occurs when the wind ratio is a smallinteger, the most severe period corresponding to the wind ratio 1:1.With wind ratios comprising ratios of small integers, the patterninggenerally will not be as intense, nor as densely distributed over thepackage surface.

Such a sudden alteration in the spindle speed during a winding programmewill have no marked adverse etfects on the fabric into which the yarnso-wound is made up, as the consequent increase in yarn Winding-ontension is acceptable in that the physical properties of the yarn arenot appreciably affected by such a sudden change in the windingconditions. A change in the spindle speed of say, 20% may cause theballoon tension to alter by about 40%.

It will be appreciated that without making provision in the spindlespeed programme to ensure that the balloon tension is maintained at asubstantially constant value throughout the winding of each package, inthe manner described above, the value of the balloon tension may varyover a wide range during the winding of such a package, for example, ifthe spindle speed is kept at a constant value, the balloon tension maychange by as much as 250%.

In the over-end winding of conically-ended package, the wind ratioscorresponding to the most enhanced periods of patterning of the packagesurface, in approximate order of severity of patterning are as follows:

1:1; 2:1; 3:1; 1:2, 3:2 and :2; 1:3, 2:3, 4:3, 5:3, 7:3 and 8:3.

In order to reduce the patterning to negligible proportions, all thepatterning corresponding to the wind ratios listed above should beeliminated, or substantially reduced, and possibly also the patterningcorresponding to the wind ratios which are multiples of 1:4 up to 11:4.The Wind ratios which are multiples of 1:5; 1:6; etc. are of relativelyminor, importance and may be ignored, although clearly a furtherimproved package would be obtained by the elimination of, or thereduction in the extent of, some, or all, of these wind ratios.

It is necessary to make a small correction to the equation S=T+W, givenabove, if strict accuracy is to be observed. Firstly, account must betaken of any yarn retraction on the package after it has been wound, ifthis yarn is of synthetic polymeric material which is subject to thiseffect.

Such retraction of the yarn causes the package as a whole to retract,and so relevant changes in package diameter will occur.

In addition, in comically-ended packages in which the yarn lay is in theform of closely-wound helical turns having superimposed thereon asinusoidal motion, account must be taken of this sinusoidal component ofthe winding motion in predetermining the values of the package diametersat which enhanced patterning is to be expected.

In this way an error of approximately 4% in the calculated value for thepackage diameter may occur.

Conveniently the profile of the cam 36 is adjustable (or conforms tothat of an adjustable cam), so that the desired spindle speed programmemay be determined initially in an empirical manner.

The basic profile of such an adjustable cam would be such that the speedof the spindle of the winding apparatus is reduced during the winding ofa package, except where knuckles are displaceably attached to thesurface of the cam, the spindle speed being increased when thecam-follower engages these knuckles. The cam should be profiled so thatat a position mid-way between adjacent knuckles the spindle speed issuch that the desired balloon tension is maintained in the yarn, whileat the position immediately before the engagement of a knuckle thespindle speed is, say, below the value required in order to give thisdesired balloon tension at that position.

These knuckle positions coincide with the points in the windingoperation when the most enhanced patterning of the package surfaceoccurs.

The effect of each knuckle is to cause the spindle speed to riserapidly, from this value below, to the same value above the spindlespeed required to maintain this desired balloon tension. The spindlespeed is then arranged to fall gradually before engaging the nextknuckle, to a value corresponding to a balloon tension 10% below thepredetermined value at the point corresponding to this next successiveknuckle.

The positions of the knuckles are deter-mined during the initialsetting-up of the apparatus.

As stated above, knuckle positions can best be determined empirically,rather than by determining the ab solute values for the traveller speedor winding-on speed or even by a determination of the relevant packagediameters, a knuckle being secured to the cam profile where patterningis observed during the previous production of a yarn package.

It may not be necessary for the spindle speed to be increased by as muchas 20% at the patterning points so as to reduce effectively the extentof the patterning, although a spindle speed change as low as 6% mayprove to be satisfactory, in the case of the patterning conditionsassociated with certain of the points defined above. Thus knuckles ofvarious heights are used, the height of each knuckle corresponding tothe spindle speed change required at that point in the windingoperation.

Instead of the variable-pitch pulley and cam arrangement describedabove, other forms of programming means, for example, electrical orelectronic devices may be employed, for example, by having a main motorfor the draw rolls etc. and a separate motor for the spindle, theprogramming means being associated with this latter motor, so as tocontrol the spindle speed in the desired manner. However in each form,when patterning is encountered, the spindle speed is arranged to beincreased so that the patterning condition is passed through quicklyand, hence, its effect either to be reduced or eliminated.

A modification of the winding apparatus of the draw twist machinedescribed above includes a different form of device for controlling thespindle speed in accordance with the programme embodied in the cam 36 ofFIG- URE 3.'This control device 60 is electrical in form and isillustrated in FIGURE 6, and will now be described, those parts whichare identical to corresponding parts described above being given thesame reference numerals, and will not be referred to again except Wherenecessary for an understanding of the manner of operation of thismodification.

In this arrangement the spindle 12 is driven by a synchronous DC. motor(not shown), individually of the main drive means which drives the drawrolls and feed rolls of the draw twist machine.

The current supplied to the DC. motor is controlled by a referencevoltage from a linear potentiometer 61, the slider 62 of which isrigidly secured to the cam follower 63 of the programming cam 35. Thus,the spindle speed is varied as in the previously described embodiment,the value of the spindle speed being determined by the position of theslider 62 of the potentiometer '61 the output of which is connected tothe DC. motor by a lead 64.

Conveniently the reference voltage from the potentiometer 61 is comparedwith that obtained from a tacho-generator connected to the output shaftof the DC motor.

The error signal obtained by this comparison is then used to alter thesetting of the D.C. motor.

Trimming rotary potentiometers (not shown) may be provided at either endof the linear potentiometer '61, each having a range of approximately20% of the linear potentiometer range, and are used to control the rangeof the linear potentiometer.

This control arrangement for the Winding apparatus is of particularapplication Where it is required to control also the start-up andslow-down performance of the draw twist machine, during the productionof each yarn package, in order to reduce yarn breakages, which are morelikely to occur at these points in the winding of a package, thanintermediate therebetween.

Thus an electrical timer may be included in the apparatus so that thedraw rolls are not operably connected to the drive means until say, 4seconds, after the spindle has been so connected.

A second timer which controls the slow-down performance of the drawtwist machine may also be provided. In such an arrangement atacho-generator monitors the speed of the main drive means motor, andfeeds back a signal to the DC. motor to drive it against brake pressureacting on the spindle during the slow down of the machine. Thus bothmotors slow down with speeds which are a predetermined ratio of eachother, the draw-rolls slowing down freely and the timing of theapplication of the brake to the spindle is controlled so as to maintaina traveller speed of at least 2,000 rpm.

A cheese winding arrangement according to the present invention is shownin FIGURE 7. This arrangement comprises a synchronous electric motor theoutput shaft 71 of which drives a spindle 72 on which the cheese 73 isbeing formed, the cheese container 74 being clamped to the spindle 72 inany convenient way.

Conventional traverse yarn guide means, indicated generally at 75,comprises a reciprocating yarn guide 76 in the form of an open-endednotch, and is driven by a secand synchronous electric motor 77, via avariable pitch pulley arrangement, shown at 78, the traverse guide speedbeing varied in accordance with the profile of a control :am (notshown).

The yarn is delivered to the yarn guide at a constant speed from afeeding device (not shown) and hence the speed of the output shaft 71 ofthe motor 70, and the rotational speed of the package 73 is arranged tobe con- :inuously reduced throughout the winding of each package, as thecheese diameter increases. To arrange that the winding-on speed of theyarn is identical to the yarn delivery speed, and there is no build upof tension within the yarn, a conventional sensing head 80 is positionedin the yarn path, the output of which head controls the output of themotor 70 via a known form of servo-device, indicated diagrammatically at81.

The appearance, and manner of formation of ridging 3n cheeses, isindicated in FIGURE 8a, which shows in an exaggerated way the lay of theyarn on a cheese. For the sake of clarity, the angle of lay of the yarnhas been increased, the value of this angle, normally being of the orderof 1. As illustrated in FIGURE 8b this angle is also equal to the helixangle as defined herein, ridging being pronounced on cheeses at certainpackage diame- :ers throughout the winding operation when this angle isin excess of 1, but will not be so enhanced when the "helix angle 0 isabout, say,

In FIGURE 8a the lay of the yarn on the cheese when the wind ratio is,say, 2:1 is shown, this being when the :raverse yarn guide executes oneoscillation along the spindle axis per two spindle revolutions andsynchronisation of the winding occurs.

Under such winding conditions the yarn of one layer is laid on top ofyarn laid in the layers immediately previously, and a ridge of yarn isformed along the whole length of each layer.

However the yarn will not be so laid, in the form of ridges, when thespeed of the traverse yarn guide is vared, or the package diameteralters so that the wind ratio l.995:1 or 2.005:1.

Care must be taken to ensure that a wind ratio corresponding to a periodof enhanced ridging does not occur tear to the outside of a completedcheese, or that the de- :rease in traverse guide speed included in thewinding arogramme, is not such that the one period of enhanced idging isavoided but another period is entered immeliately afterwards.

It will be appreciated that, whereas for over-end winding ofcomically-ended packages any change in the traveler speed willsubstantially affect the winding conditions, ;uch that it is desirablethat the traveller speed should be ncreased rather than decreased duringthe winding op- :ration, with cheese winding the winding conditions areess sensitive to changes in the traverse yarn guide speed, indconsequently this speed conveniently may be de- :reased or increasedduring the winding operation.

As in the case of over-end winding, a reduction in the lam traverseguide speed will imply that the patterning zone occurs at relativelylarger package diameters than if his speed is increased. Consequently,by decreasing the Jam traverse guide speed it may be possible to avoidthe )atterning regions in a cheese of a predetermined size.

However, if the period of patterning is traversed by in- :reasing thetraverse guide speed, then this period will lave to be traversed againat a larger package diameter, Jy decreasing the traverse guide speed, sono advantage s gained.

The wind ratios corresponding to a period of enhanced 'idging, andnormally encountered in the winding of :heeses are the integers 2:1 upto 8:1 and the ratios of small integers in between these values.

Again, the determination of the points in the cheese 16 windingoperation at which ridging occurs, is best done in an empirical manner.

When the relevant package diameters have been determined, the method ofprogramming the winding apparatus will be identical to that describedabove with reference to the formation of conically-ended packages byover-end winding. The cam embodying such a cheese winding programme willresemble the cam 36 illustrated in FIGURE 3.

Winding apparatus according to the present invention, including meansfor increasing the spindle speed at predetermined points during thewinding operation of each package, may include also means for scramblingthe spindle speed, which means also will tend to eliminate ridging orpatterning.

Account may have to be taken, in this respect, according to whether theyarn being wound is either a monofilament or a multifilament yarn.

In each illustrated arrangements, the increase in the speed of thespindle (or the yarn traverse guide device) will be relatively fastcompared to the overall time required to wind each package, for example,a spindle speed increase of, say, 1000 rpm. being made in less than 0.5%of the package winding cycle, say, in 7.5 seconds.

It is essential that at the time in the winding operation at which theincrease in spindle speed (or traverse guide speed) is initiated by theprogramming means, that it is within 1% of the predetermined programmefor the winding apparatus.

In each embodiment described above, the accuracy with which theprogramme embodied in the cam is reproduced by the winding apparatus, ismainly dependent upon the accuracy of the motor controlled by the cam,and this will normally be of the order of /2 What we claim is:

1. Apparatus for producing a cylindrically-wound yarn package on aspindle, in which package the yarn is laid with a helix angle in excessof one degree, there being predetermined points during the formation ofsuch a package associated with periods during which the yarn turns mergetogether to form ridges, each period of enhanced ridging correspondingto winding conditions having associated therewith a wind ratio thenumerical value of which is either a small integer or a ratio of smallintegers, including programming means having a profiled cam which makesone revolution between the winding of successive packages and embodiesthe desired spindle speed program whereby the winding conditions arecontrolled and caused to produce an increase in the numerical value ofthe wind ratio at predetermined points in the winding operation so as toreduce the extent of the periods of enhanced ridging in the formation ofthe package.

2. Apparatus having over-end winding guide means, and for producing acomically-ended yarn package on a spindle, in which package the yarn islaid with a helix angle in excess of one degree, there beingpre-determined points during the formation of such a package associatedwith periods during which the yarn turns merge together to form asurface relief pattern effect, each period of enhanced patterningcorresponding to winding conditions having associated therewith a windratio the numerical value of which is either a small integer or a ratioof small integers, which includes programming means having a profiledcam which makes one revolution between the winding of successivepackages and embodies the desired spindle speed program whereby theWinding conditions are controlled and caused to produce an increase inthe spindle speed at the pre-determined points in the winding operation,so as to reduce the extent of the periods of enhanced patterning in theformation of the package.

3. Apparatus as claimed in claim 2 in which the programming meanscomprises an electrical device, and includes a potentiometer, theposition of the slider of this potentiometer being controlled by thecam, and the output signal from the programming means controlling thespindle speed.

4. Apparatus for producing a cheese on a spindle, and including areciprocating yam traverse guide, the rotational speed of the spindlebeing arranged to be proportional to the ratio of the yarn deliveryspeed to the package diameter, and the speed of the traverse yarn guidebeing variable independently of the spindle speed at will, and in whichcheese the yarn is laid with a helix angle in excess of one degree,there being pre-determined points during the formation of such a cheeseassociated with periods during which the yarn turns merge together toform ridges, each period of enhanced ridging correspond ing to windingconditions having associated therewith a wind ratio the numerical valueof which is either a small integer or a ratio of small integers, whichincludes programming means having a profiled cam which makes onerevolution between the winding of successive packages and embodies thedesired spindle speed program whereby the winding conditions arecontrolled and caused to produce an increase in the numerical value ofthe wind ratio at pro-determined points in the winding operation, andthereby reduce the extent of the periods of enhanced ridging in theformation of the package.

5. A method of producing a cylindrically wound yarn package on aspindle, in which package the yarn is laid with a helix angle in excessof one degree, there being predetermined points during the formation ofsuch a package associated with periods during which the yarn turns mergetogether to form ridges, each period of enhanced ridging correspondingto winding conditions having associated therewith a wind ratio thenumerical value of which is either a small integer or a ratio of smallintegers, which comprises controlling the winding conditions to cause anincrease in the numerical value of the wind ratio at the predeterminedpoints in the winding operation, so as to reduce the extent of theperiods of enhanced ridging in the formation of the package.

6. A method of producing a conically-ended yarn package on a spindle, inwhich package the yarn is laid with a helix angle in excess of onedegree, there being predetermined points during the formation of such apackage associated with periods during which the yarn turns mergetogether to form a surface relief pattern elfect, each period ofenhanced patterning corresponding to winding conditions havingassociated therewith a wind ratio the numerical value of which is eithera small integer or a ratio of small integers, which comprisescontrolling the speed of the spindle to cause an increase in the spindlespeed at the predetermined points in the winding operation, so as toreduce the extent of the periods of enhanced patterning in the formationof the package.

7. A method as claimed in claim 6 in which the spindle speed is arrangedto be reduced intermediate between the predetermined points.

8. A method as claimed in claim 6 in which the increase in spindle speedat each predetermined point is arranged to be less than 20% of the meanvalue of the spindle speed at that point in the winding operation.

9. A method as claimed in claim 6 in which the increase in spindle speedat each predetermined point, and embodied in the spindle speed program,is arranged to be the minimum requisite value in order to avoidpatterning at that point in the Winding operation, the value of thisincrease varying between different predetermined points. a

10. A method as claimed in claim 6 in which the requisite increase inspindle speed at each predetermined point in the winding operation isarranged to be effected during a period less than 0.5% of the packagewinding period.

11. A method of producing cheeses on a spindle, in which the rotationalspeed of the spindle is arranged to be proportional to the ratio of theyarn delivery speed to the package diameter, and the speed of areciprocating traverse yarn guide is arranged to be independentlyvariable of the spindle speed at will, and in which cheese the yarn islaid with a helix angle in excess of one degree, there beingpredetermined points during the formation of such a cheese associatedwith periods during Which the yarn turns merge together to form ridges,each period of enhanced ridging corresponding to winding conditionshaving associated therewith a wind ratio the numerical value of which iseither a small integer or a ratio of small integers, comprisescontrolling the speed of the traverse yarn guide to cause an increase inthis speed at the predetermined points in the winding operation, so asto reduce the extent of the periods of enhanced ridging in the formationof the package.

References Cited UNITED STATES PATENTS 3,009,308 11/1961 Bromley et a1.57-55.5 3,137,987 6/1964 Potts 57S5.5 3,334,828 8/1967 Harrison 24226.12,529,559 11/1950 Kreamer.

2,764,363 9/1956 Stammwitz 242-26.3 3,130,930 4/1964 Miller 242-263 JOHNPETRAKES, Primary Examiner US. Cl. X.R.

